Getting Static Property from a Class with Dynamic Class Name in PHP

Getting static property from a class with dynamic class name in PHP

If you are using PHP 5.3.0 or greater, you can use the following:

$classname::$$propertyname;

Unfortunately, if you are using a version lower than 5.3.0, you are stuck using eval() (get_class_vars() will not work if the value is dynamic).

$value = eval($classname.'::$'.$propertyname.';');

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EDIT: I've just said get_class_vars() wouldn't work if the value is dynamic, but apparently, variable static members are part of "the default properties of a class". You could use the following wrapper:

function get_user_prop($className, $property) {
  if(!class_exists($className)) return null;
  if(!property_exists($className, $property)) return null;

  $vars = get_class_vars($className);
  return $vars[$property];
}

class Foo { static $bar = 'Fizz'; }

echo get_user_prop('Foo', 'bar'); // echoes Fizz
Foo::$bar = 'Buzz';
echo get_user_prop('Foo', 'bar'); // echoes Buzz

Unfortunately, if you want to set the value of the variable, you will still need to use eval(), but with some validation in place, it's not so evil.

function set_user_prop($className, $property,$value) {
  if(!class_exists($className)) return false;
  if(!property_exists($className, $property)) return false;

  /* Since I cannot trust the value of $value
   * I am putting it in single quotes (I don't
   * want its value to be evaled. Now it will
   * just be parsed as a variable reference).
   */
  eval($className.'::$'.$property.'=$value;');
  return true;
}

class Foo { static $bar = 'Fizz'; }

echo get_user_prop('Foo', 'bar'); // echoes Fizz
set_user_prop('Foo', 'bar', 'Buzz');
echo get_user_prop('Foo', 'bar'); // echoes Buzz

set_user_prop() with this validation should be secure. If people start putting random things as $className and $property, it will exit out of the function as it won't be an existing class or property. As of $value, it is never actually parsed as code so whatever they put in there won't affect the script.

PHP Access static property from dynamic class name

I solved it.

The static variable can be accessed by:

public function getMyVar($classname) {
    return $classname::$myvar;
}

That was a lot easier than anticipated! :)

How to access static property and static constants of another Class Dynamically

comment line 11 and 12 and try to var_dump this->config and you'll see that it is not picking the whole object but just the __construct because you are calling static methods on an object so try the following code

        class HelloAction
        {
            const FIRST = "DEMO";
            public static $first = "WORLD";
            function __construct($confclassname)
            {
                $this->config = $confclassname;
                # PHP Interpreter throws an Error for These Two Lines
                $this->first1 = $confclassname::$a;
                $this->first2 = $confclassname::$b;
            }

            function setFirst($s)
            {
                self::$first = $s;
            }
        }

        class action1
        {
            const AAAA = "____Hello World____";
            public static $a = "this is an apple";
            public static $b = "That is an Dog";
            function __construct()
            {
                $this->second = "hi, there.";
            }
        }

        class action2
        {
            const AAAA = "___Yeah, Hello World____";
            public static $a = "Whare You were...";
            public static $b = "Awesome work";
            function __construct()
            {

            }
            public static function action21($s)
            {
                self::$a = $s;
            }
            public function action22()
            {
                return self::$a;
            }
        }

        $b1 = new HelloAction('action1');
        $b2 = new HelloAction('action2');

        echo $b1->first1 . "\n";
        echo $b1->first2 . "\n";

        ?>

Setting a static class property dynamically with squiqlies

You can't set dynamically a static property (otherwise wasn't static :P), but you can manage it, example

class Foo {
    static $vars;
    public static function set( $k, $v ){
        self::$vars[$k] = $v;
    }
    public static function get( $k ){
        return isset(self::$vars[$k]) ? self::$vars[$k] : 'error';
    }
}

accessing static methods using a variable class name (PHP)

That syntax is only supported in PHP 5.3 and later. Previous versions don't understand that syntax, hence your parse error (T_PAAMAYIM_NEKUDOTAYIM refers to the :: operator).

In previous versions you can try call_user_func(), passing it an array containing the class name and its method name:

$variable_class_name = 'foo';
call_user_func(array($variable_class_name, 'bar'));

PHP how to set static variable from a string

You can use a plain variable variable name:

static function databaseInit( $database ){
    self::$$database = true;
}

.. but you should really rework it to just keep an array and manipulate the keys of the array instead, as that will keep all the settings inside a single namespace instead of potentially doing weird stuff with other static variables if a name is mistyped, etc.

class app {
    static $databases = [];

    ...

    static function databaseInit($database) {
        self::$databases[$database] = true;
    }
}

And the next step would be to make the class non-static instead, so it can be easier tested and will keep its state locally instead.

Access Static properties using PHP object

Static properties may be accessed on various ways.

Class::$aStaticProp; //by class name

$classname::$aStaticProp; // As of PHP 5.3.0 by object instance

Static properties cannot be accessed through the object using the arrow operator ->.

As of PHP 5.3.0, it's possible to reference the class using a variable. The variable's value can not be a keyword (e.g. self, parent and static).

More you can read in manual

Access a static variable by $var::$reference

You can use reflection to do this. Create a ReflectionClass object given the classname, and then use the getStaticPropertyValue method to get the static variable value.

class Demo
{
    public static $foo = 42;
}

$class = new ReflectionClass('Demo');
$value=$class->getStaticPropertyValue('foo');
var_dump($value);

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